Induction-machine.



A A. H. NEULAND.

INDUCTION MACHINE. APrLlcATiON FILED ocr. 2. 1.913.

Patented Aug. 21, 1917.

'ff-*1 HMT Wt/wss V 1 UNITED? sTATEs PATENT oEEIoE.

ALFONS H. NEULAND, 01" SAN FRANCISCO, CALIFORNIA, ASSIGNOR T0 NEULANDELECTRICAL COMPANY, INC., A CORPORATION 0F NEW YORK.

INDUCTION-MACHINE.

To all whom t may concern: Be it known that I, ALFoNs H. NEULAND, asubject of the Czar vof Russia, and a resident of the city7 and countyof San Francisco, State of California, have invented certain new anduseful Improvements in Induction-Machines, of which the following is aspeciication. y he invention relates to induction generators and motors.

The object of the invention is to provide a variable speed inductionmotor.

Another object of the invention is to provide an induction machinecapable of operating at a variable speed and a variable torque -as wellas a simple means of starting a motor from rest.

Another object of the invention is to provide a method of varying thetorque of an induction machine without varying the resistance of thesecondary winding and without varying the primary windings.

The invention possesses other objects and advantageous features, which,with the foregoing, will be set forth at length in the followingdescription where I shall outline in full that form of the inventionwhich I have selected for illustration in the drawings accompanying andforming part of the present specification. The novelty of the inventionwill be included in the claims succeeding said description. From this itwill be apparent that I do not limit myself to the showing made by saiddrawings and description, as I may adopt many variationswithin the scopeof my invention as set forth in said claims.

One of the features of the invention is the production in an inductionmachine, of a variable speed and torque by changing the relation to eachother of two revolving magnetic fields which act upon a mutual secondarywinding. By varying the relation of the fields to each other, the pathof the uX through the secondary winding is varied, thereby producing avariation in the speed and torque of the machine. For the purpose ofconvenience, I shall describe the invention as applied to an inductionmotor, it being evident that the machine will also work as an inductiongenerator if operated in connection with synchronous generators,

i or if excited by any of the means known to the art.

As in all induction machines, the speed of Specification of LettersPatent.

Application filed. October 2, 1h13. Serial No. 793,055.

the rotating field or ields is fixed by thel frequency of thealternating current supply and the number of pole windings on thestator. The stator windings of the present machine may be the same asthe stator windings of induction machines in general use, or of any typecapable of producingv a revolving field.

Referring to the drawings accompanying the application;

Figure l is an end view partly diagrammatic, of one form of the machineof my invention. i i

Fig. 2 is a longitudinal section of the machine sho-wn.in Fig. l. l

Fig. 3 is a diagram showing the path of the flux in the machine shown inFig. l for a certain relative position of the two rotating fields.

- Fig. d is a similar diagram showing the path of the flux for anotherrelative position of the two elds.

Fig. 5 is a diagrammatic end view of a.

tayp having but a single revolving magnetic Fig. 6 is a longitudinalsection of the machine shown in F ig. 9, the dotted lines indieatingdierent positions of the inner core.

Fig. 'i' is a diagrammatic view of a modified form of means for movingone ield relative to the other, by means of mova'ble contacts.

Figs. 8 and 9 are similar views showing the contacts moved to otherpositions, to change the relative positions of the two rotating elds.

The machine illustrated in Figs. 1 and 2 is a two pole two phasemachine7 but it is evident that machines may be, readily designedemploying a different number of poles and it is to be understood that Ido not limit myself to a two-phase machine. The present machine is a twopole arrangement with but a single slot per pole and phase. Thisarrangement has been chosen for the sake of simplicity in illustrationand description, but a distributed winding may be equally well employed.The machine consists of a laminated stator 2 having four projections 3,4', 5, 6, on which are arranged the windings producing the. revolvingfield, one pair of opposite pole projections being encircled by thewindings of one phase and the other pair of opposite poleprojectionsbeing encircled by t e windings of the second phase, so that a rotatingfield is produced.

Arranged concentrically with respect to the poles 3, 4, 5 and 6 is therotor 7 formed of ring shaped laminations, in which are embedded orarranged the longitudinally extending bars 8 9. These bars are arrangedin two circumferential series, the bars 8 lying in the outer series andthe bars 9 lying in the inner series. The bars 1n each series are spacedregularly circumferentially, a bar in one series and a bar in the otherseries forming a pair. The bars project from the ends of the rotor andeach pair of bars, that is, one in each series, are connected togetherat their ends by straps i2, thereby short circuiting each pair of bars.These bars and straps form the secodnary winding of the machine. Therotor 7 is mounted upon a suitable rotatable shaft 13 from which poweris taken od or applied.

Arranged concentrically with regard to the rotor.7 is a second core orstator 14 mounted on a shaft 15 so that the core 14 may be moved withrespect to the stator 2. Any suitable means may be employed to vary therelative position of the inner and outer stators and hold them in suchposition. The inner stator is provided with the same number of poleprojections 16 17 18 19.as the stator 2 and the pole projections areprovided withwindings connected to the alternating current supply toproduce a revolving field, which has the same angular. velocity as thefield of the stator 2. With the two magnetic fields ro tating at-thesame angular velocity it is evident that a pole of one polarity onstator 2 is always opposed by a pole of opposite polarity on. stator 14when the parts are in the position indicated in Fig. 1; The flux,therefore, passes from pole 3 radially through the rotor to pole 16,across the stator 14 to pole 18, radially through the rotor to pole 5and completes the circuit back to pole 3 through the stator 2. The linesof force are, therefore, not cutting the short circuited secondarywindings of the rotor formed by the bars 8 9, and, consequently, noelectromotive force is induced in the bars, no force is exerted on thebars and the rotor therefore remains stationary. Y

The cuirrent which circulates in the primary winding 5, therefore, is ofsuch magnitude as would be the case in an induction motor'with an opensecondary.

If, however, the stator 14 be rotated with respect to the stator 2, sothat the oppositely magnetized poles are not directly opposed, the fluxin passing from one stator to the other must pass through some of theclosed circuits formed by the ba-rs 8 9. In Fig. 3 I have shown thepathofthe flux when the stator 14 is moved 90 degrees with respect to theposition shown in Fig. 1,

bringing pole winding 16 opposite pole winding 4. In this position,the'flux passes from pole 3, through rotor 7 for a quarter circle,therebv producing'a current in the bars within that quarter circle, topole 16, whence it passes to pole 18, through rotor 7 for a quartercircle to pole 5, and thence through stator 2 to pole 3, completing themagnetic circuit. In this position of the stator 14, one h alf of therotor circuits are effective to exert a torque on the rotor. In Fig. 4,I have shown the path of the flux when the stator 14 has been moved to aposition 1800 removed from the position shown in Fig. 1 or in otherwords to a position in which the opposing poles of the two stators areof like sign. -When in this position, the flux produced by the 4windingson stator 2 passes circumfercntially in opposite directions through therotor to the opposing pole of stator 2, and the flux produced by thewindings on stator 14 passes crcumferentially in opposite directionsthrough the rotor to the opposing pole of stator 14, causingsubstantially all of the rotor circuits to be out by the flux andinducing a current in said circuits.

Therefore, by shifting the position of stator 14 with respect to stator2, the flux is made to traverse a lesser orgreater number of the shortcircuited bars resulting in a variable torque.

In Figs. 5 and 6 I have shown an induction machine in which only onestator is employed. The stator 2 issimilar to the stator shown in Fig. 1and is wound in the same manner. The rotor 7 is identical with the rotorshown in Fig. 1. Arranged within the rotor is a laminated core 26carrying no windings and capable of being moved longitudinallywith'respect to the stator. When the core 26 lies wholly within thestator, the flux passes from one pole of the stator directly across therotor and core to the other pole of the stator of opposite sign withoutcutting the rotor bars. When the core is moved partly out of the stator,the resistance to the passage of the fiux across the inner coreincreases, causing a portion of the flux to pass circumferentiallythrough the rotor, inducing a current in the rotor winding and settingit in motion. When the vcore is entirely withdrawn. from within the'stator, the total flux passes circumferentially through the rotor,inducing a large current in the rotor bars and consequently producing apowerful torque.

In Figs. 7 to 9 inclusive I have shown a modified form of construction,in which the `relative movement. of the rotating fields is accomplishedelectrically instead of mech'anically. The coils or windings 31 32 Ipreferably arranged circumferentially and are adapted to be engaged bybrushes 29 connected to the feed These brushes are arranged on asuitable rotatable frame so that the brushes may be moved relative tothe contacts, so that the phase relation of the coils with -respect tothe stator may be varied. In Fig. 7, coils 31 and 32 are connected toone phase and coils 33 and 34 to the second phase. In Fig. 8, thebrushes have been moved in a countercloclwise direction, through theangle between the successive contacts, causing coils 31 and 34: to

be in one phase and coils 32 4and 33 to be in the second phase, orcausing a relative movement of the field in one stator with respect tothe eld in the other stator of o.. In Fig. 9, the brushes have beenmoved another 450 in a countenclockwise direction, placing coils 33 and3i in one phase and coils 31 and 32 in the second phase, producing arelative movement of the field in one stator with respect to the fieldin the other stator.

I claim:

1. In an induction machine, a longitudinally stationary laminated rotorprovided with a closed winding, means including iiXed poles carryingpolyphase windings for producing a substantially constant magnetic Euxacting on said rotor and means for altering the path of said flux insaid rotor, whereby the magnetic flux is diverted rom said winding.

2. In an induction machine, longitudinally stationary laminated rotorprovided with a closed winding, means for producing a revolving magneticfluir `-acting on said l winding, and means for diverting the magneticlinx from said winding, while maintainingthe iiux traversing said rotorsub? stantially constant.

3. In an lnduction machine, a rotor comprising alaminated ring, a seriesof bars embedded in said ring at its outer circumference, a series ofbars embedded in said ring at its inner circumference, a bar in'oneseries and a bar in the other series forming a palr, conductorsconnecting both ends of each pair, means including two stationaryelements for producing a magnetic flux actmg on said pairs and means forcircumferentially changing the relative positions of the fluxes in thestationary elements whereby the number of pairs of bars traversed by themagnetic flux is varied.

4. In an induction machine, a rotor comprising a laminated ring, aseries of bars embedded in said ring at its outer circum- I ference, aseries of bars embedded in said of the inner series forming closedloops, means for producing a revolving magnetic iuX traversing saidclosed loops, and means for diverting the flux from said closed loops.

5. In an induction machine, a stationary element provided with polyphasewindings arranged to produce a revolving magnetic flux, a rotor carryinga secondary winding and means fer varying the length of the path of saidflux in the rotor whereby the number of closed turns of the secondarywinding traversed by the said flux is varied.

6. In an induction machine, a stationary laminated element carrying aprimary winding producing a rotating magnetic flux, a second stationarylaminated element arranged within and concentric with-said iirststationary element producing a second rotating ux of equal angularvelocity to that of the first flux, an annular laminated rotorarrangedbetween said stationary elements and a closed secondary winding on saidrotor acted on by the iuxes of the irst and second stationary elementsand means for changing the circumferential positions of the fluxes ofthe two stationary elements, thereby diverting the flux from the closedturns of the secondary winding.

7. In an induction machine, a stationary laminated element carryingaprimary winding a second laminated element arranged wit in andconcentric with said first element and carrying a second primarywinding, a laminated ring adapted to be rotated arranged between saidlaminated elements, a series of bars embedded im said ring adjacent itsouter circumference, a series of bars embedded in said ring adjacent itsinner circumference and means conductively connecting the ends of eachbar in one series with the ends of an adjacent bar in the other series.

8. In an induction machine, a stator provided with a polyphase primarywinding, a rotor arranged within said stator, a plurality of barsextending longitudinally of said rotor, said bars being arranged inpairs, straps connecting both ends of each pair to produce a pluralityof closed circuits, a stator provided with a' polyphase primary winding,arranged within said rotor', and means for varying the position of saidsecond stator with regard to the first stator;

9. In an induction machine, a rotor comprising a laminated ring, aseries of bars embedded in the rin at its outer circumference, a seriesof ars embedded in the ring at its inner circumference, a bar in oneseries and an adjacent bar in the other series forming a pair, andconductors connecting both ends of each pair. y v

10. In an induction machine, a stationar laminated element carrying aprimary winj ing adapted to be 4fed by an alternating current to producerotating magnetomotive 'foi-ces, a second stationar laminated elementarranged Within an concentric with lsaid first stationary element andcarrying a primary winding adapted to be fed by an alternating currentof the same frequency to produce rotating magnetomotive' forces of thesame angular velocity as those of 'the first stationary element, anannular laminated rotor/arranged between said sta.- tonary element, aseriesl of conductors embedded adjacent the outer circumference and aseries of conductors embedded adjacent the inner circumference of saidrotor, the conductors being connected at their ends forming a rotorwinding composed of closed turns, the flux due to the magnetomotiveforces of the first and second stationary elements acting on said rotorwinding and means for changing the relation of the magnetomotive forcesof the first stationary ele- 'ment to the magnetomotive forces of thethe roto r In testimony whereof, I have hereunto V set my hand at SanFrancisco, California, this 26th day of September, 19,13.

ALFONS H. NEULAND.

In presence of- H. G. PRos'r, P. S. PIDWELL.

